The present invention relates to polishing pads useful in the manufacture of semiconductor devices by chemical mechanical polishing of semiconductor substrates such as silicon dioxide, silicon, metal, dielectric materials (including polymeric dielectric materials). The polishing pad of this invention has a polishing layer comprising hard domains and soft domains.
U.S. Pat. No. 5,197,999 describes a polishing pad with a soft matrix material and discrete particles distributed substantially uniformly throughout the matrix to effect stiffening of the polishing pad.
Chemical mechanical polishing (CMP) is an enabling technology for the production of complex and dense semiconductor structures on semiconductor substrates and is an effective method for the removal and planarization of thin films on semiconductor substrates during the production of integrated circuits including multi-chip modules, capacitors and the like. Semiconductor device fabrication generally requires CMP of one or more substrates, such as silicon, silicon dioxide, tungsten, copper or aluminum. Due to fine feature geometries of semiconductor devices, semiconductor substrates must be precision polished by CMP to narrow tolerances.
In known CMP, the semiconductor substrate to be polished is mounted on a carrier or polishing head of a polishing machine. The exposed surface of the substrate is placed against a rotating polishing pad. Typically, polishing pads used in CMP comprise a polymeric layer that contacts the semiconductor substrate being polished and is referred to herein as the polishing layer. The polishing pad may be a standard pad (without any abrasive particles in the polishing layer), also referred to herein as a non fixed-abrasive pad, or a fixed-abrasive pad (containing abrasive particles in the polishing layer). The carrier head provides a controllable pressure (or downforce), on the substrate to bias it towards the polishing layer of the polishing pad. A polishing fluid with or without abrasive particles is then dispensed at the interface of the substrate and the polishing layer of the polishing pad to enhance removal of the target layer (for e.g., metal layer in first-step CMP or barrier layer in second-step CMP) on the substrate. The polishing fluid is preferably water based and may or may not require the presence of abrasive particles, depending on the composition of the polishing layer of the polishing pad. An abrasive-free polishing fluid also referred to as a reactive liquid is typically used with a fixed-abrasive pad. A polishing fluid containing abrasive particles, also referred to herein as slurry, is typically used with a non fixed-abrasive pad.
In the context of this invention the term xe2x80x9cpolymerxe2x80x9d includes: various types of copolymers such as random copolymers, branched copolymers, block copolymers, multi-block copolymers, graft copolymers, and alternating copolymers; homopolymer blends; homopolymer and copolymer blends; and polymer blends including interpenetrating polymer networks.